Compacting apparatus



June 1966 s. GlERTZ-HEDSTROM 3,255,682

COMPACT ING APPARATUS Original Filed May 12, 1959 Fig.1

INVENTOR. STIG GIERTZ-HEDSTROM ATTORNEYS United States Patent 3,255,682COMPACTING APPARATUS Stig Giertz-Hedstrom, Knivsta, Sweden, assignor toAktiehoiaget Vihro-Verken, Stockholm, Sweden, a corporation of SwedenContinuation of application Ser. No. 812,748, May 12, 1959. Thisapplication June 9, 1964, Ser. No. 373,702 Claims priority, applicationSweden, Nov. 12,1958,

0,478/58 1 Claim. (Cl. 9450) The invention disclosed and claimed hereinis a continuation of application Serial No. 812,748, filed on May 12,1959 in the United States Patent Office and now abandoned.

This invention, generally, relates to compacting apparatus and, moreparticularly, to apparatus of the type adapted for use in compactingearth, gravel, and other materials in construction projects.

In the past, vibratory as well as nonvibratory rollers have been used,for example, in road building and the like. The vibratory type of rollerhas been found to exhibit excellent compacting abilities which aredesirable for compacting earths of the non-clay type, whereas vibratoryrollers offer very little compacting effect in earths having high claycontent, due to the high elasticity of clayish earths.

To compact clayish earths, that is, earths having a high clay content,the practice has been to increase the surface pressure exerted on theclayish earth, primarily by increasing the weight of the roller. Anexample of such a roller is the so-called rubber wheel roller which,even though it is extremely heavy, is still incapable of effecting aparticularly high degree of compactness and, in addition, is unwieldlyand awkward to maneuver.

It also has been the practice in the past to increase surface pressureby providing the surface of a roller with radially-projecting spikes or.studs (so-called sheeps feet) which cause a kneading and caking of evenclayish earths. This type of'apparatus is superior, in certaininstances, to the compacting effect obtainable by a rubber wheel roller.

However, there are disadvantages even in the heretofore known type ofsheeps foot compacting apparatus. For example, the sheeps foot apparatusused in the past compacts only a relatively shallow layer of earth andthe compacting achieved during each pass over a particular area isdependent directly upon the radial length and the face area of eachsheeps foot. It has been found that the length of each sheeps footcannot be increased materially because, apart from the weakeningstructural effect it produces in each sheeps foot, an excessive radiallength tends to break up the earth already compacted as each thus-formedsheeps foot commencesits upward movement from the lowermost,downwardly-extending, compacting position.

Accordingly, an object of the present invention is to provide acompacting apparatus superior to any compacting apparatus knownheretofore.

It is also an object of the invention to provide a compacting apparatuswhich combines a vibratory motion with a sheeps foot apparatus topresent a unique, novel, and particularly advantageous compactingapparatus.

A further object of the invention is to provide a compacting apparatuswhich overcomes the disadvantages characteristic of compacting apparatusheretofore known.-

According to the invention, generally, a plurality of radiallyextendingprojections, or studs (so-called sheeps feet) are formed over thesurface of a roller. In addition to the arrangement of the sheeps feet,a means is provided for effecting a vibratory motion to the roller andto the sheeps feet, or projections.

The invention provides, among its advantages, a considerably moredeep-reaching and laterally reaching compacting effect as compared withheretofore-known compacting apparatus. Moreover, this advantage isachieved, according to the invention, Without the necessity ofincreasing the radial length of the sheeps feet or the weight of theroller.

Actually, according to the new and novel structural arrangement of theinvention, the vibrations generated by the vibratory unit transmitcompacting motion not only through the surface of the roller cylinderitself but, also, through the projections, or sheeps feet, thatpenetrate the ground layer supporting the roller.

In addition to the above, it has been found that highly clayish earthsdo not adhere'to the roller of the invention and, as a result thereof,the projections actually penetrate further into the earth than withcompacting apparatus heretofore known.

Other objects and advantages of the invention will became apparent toone skilled in the art to which the invention pertains from thefollowing detailed description of the presently preferred embodimentthereof, which is described with respect to the accompanying drawings inwhich similar reference characters represent corresponding parts in theseveral views and wherein:

FIG. 1 is a view in side elevation of a compacting apparatus inaccordance with a preferred embodiment of the invention; and

FIG. 2 is a plan view of the embodiment of the invention shown in FIG. 1wherein certain sections are broken away to show underlying structuralarrangements.

Referring now particularly to the preferred embodiment of the inventionfor illustrative purposes only, however, the campacting apparatusincludes a frame 1 and a cylindrical roller 2 suitably journaled tosupport the frame 1. A plurality of projections, spikes, studs, or thelike, 3 (so-called sheeps feet) are mounted on the surface of the roller2 to extend substantially radially therefrom.

A principal purpose of the projections 3 is to penetrate the material tobe compacted as the roller 2 is moved along a desired path. Of course,the projections 3 may take any of a number of possible configurations, apreferable configuration for the projections 3 being that of a truncatedpyramid, as shown for illustrative purposes in the drawings.

Extending axially througth the roller cylinder 2 is a drive shaft, oraxle 4, arranged to drive two axiallyspaced vibrators. Each of thesevibrators, known per se heretofore, has an annular rolling track 5serving as a circular race for a' ball 6. Of course, the ball 6 isentirely unrestricted concerning its freedom of movement along the track5, and the ball 6 is moved along the track 5 by means of a dog member 7which is keyed rigidly to the shaft 4.

To generate the vibratory motion in the surface of the roller cylinder 2and also in the projections 3, the shaft 4 is rotated by means of anelastic transmission in the form of a belt drive comprising one or moreV-belts 9. These belts 9 transmit power from a prime mover 8, or drivemeans, mounted on the rear portion of the frame 1.

The actual vibratory effect is amplified by a weight 10 fixedeccentrically between the vibratory units shown in the drawings. Thevibratory movements imparted to the roller 2 and the projections 3 bythe rotating elements, independently of roller rotation, are directedradially of the shaft 10. Such vibrations of the flat surfacedprojections 3 effectively compact material into which the projectionsextend.

To protect the frame 1 from the vibratory motions generated anddeveloped by the apparatus, the frame 1 is suspended from the rollercylinder 2 by resilient members 13 so that the vibratory motions are nottransmitted to the frame 1. This is advantageous not only in protectingthe drive means 8 from such vibrations, but also in preventing the frame1 and the drive means 8 from exerting a vibration-damping effect on theapparatus.

The invention may be embodied in other specific forms without departingfrom the essential characteristics thereof. Hence, the presentembodiments are to be considered in all respect as merely illustrativeand not as being restrictive the scope of the invention being indicatedby the appended claim rather than by the foregoing description, and allmodifications and variations as fall within the meaning and purview andrange of equivalency of the appended claim are therefore intended to beembodied therein.

I claim:

A compacting machine comprising a frame structure including a pair ofbearings, a hollow roller having roller bearings and carrying aplurality of radially extending, outward converging, tapered earthengaging projections, each having a face at its extremity which issubstantially parallel to the surface of the roller, the projectionsbeing arranged in a multiplicity of closely adjacent circumferentialrows whose combined base areas occupy at least one half of the surfacearea of the roller, the tapered projections in alternate rows beingstaggered in a generally checker arrangement whereby the edges of thebases of the projections in one row extend circumferentially at least tothe edges of the bases of the projections in adjacent rows and eachhaving a flat outermost surface which is generally one quarter of thearea occupied by the base of each projection, a driven rotatable shaftextending through the roller and supported by the roller bearingstherein, said shaft also being journaled in the frame bearings, avibration generator disposed in the roller including weight meansunbalanced with respect to the shaft and rotated by the shaftconcentrically therewith to impart vibratory movements to the radialprojections independently of the rotation of the roller, said vibratorymovements being directed in all radial directions from said shaft tocompact material into which the radial projections extend, drive meansmounted on the frame, and means coupling the drive means to the shaft.

References Cited by the Examiner UNITED STATES PATENTS 2,384,469 9/1945Kalix 94--50 2,677,995 5/1954 Wood 94-50 2,868,094 1/1959 Anderson 9450FOREIGN PATENTS 571,105 8/1945 Great Britain.

CHARLES E. OCONNELL, Primary Examiner.

JACOB L. NACKENOFF, Examiner.

